From http://kitenet.net/~joey/code/etckeeper/
" It hooks into apt (and other package managers including yum and pacman-g2) to automatically commit changes made to /etc during package upgrades. It tracks file metadata that revison control systems do not normally support, but that is important for /etc, such as the permissions of /etc/shadow. It's quite modular and configurable, while also being simple to use if you understand the basics of working with revision control.

etckeeper is available in git at git://git.kitenet.net/etckeeper, or in gitweb. It's packaged in Debian; packages for other distributions are forthcoming."